U.S. patent number 4,125,142 [Application Number 05/831,801] was granted by the patent office on 1978-11-14 for safety device protecting roller blinds against unrolling.
This patent grant is currently assigned to Repa Feinstanzwerk GmbH. Invention is credited to Artur Fohl.
United States Patent |
4,125,142 |
Fohl |
November 14, 1978 |
Safety device protecting roller blinds against unrolling
Abstract
A roller blind with a safety device for arresting accidental
unrolling of the blind in which a shaft butt is coupled to one end
of the winding shaft, a drive disk disposed on the shaft butt, a
pawl shaped inertial member pivotally mounted on a pin extending
from the drive disk, and a housing having internal teeth, around
the disk and inertial member. The inertial member will not change
its position relative to the drive disk but with increased
unrolling velocity does change its position and the pawl engages
the internal teeth of the housing to arrest unrolling of the
blind.
Inventors: |
Fohl; Artur (Haubersbronn,
DE1) |
Assignee: |
Repa Feinstanzwerk GmbH
(Alfdorf, DE1)
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Family
ID: |
25768983 |
Appl.
No.: |
05/831,801 |
Filed: |
September 9, 1977 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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692274 |
Jun 3, 1976 |
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Foreign Application Priority Data
Current U.S.
Class: |
160/291;
160/300 |
Current CPC
Class: |
E06B
9/84 (20130101) |
Current International
Class: |
E06B
9/84 (20060101); E06B 9/80 (20060101); E06B
009/208 () |
Field of
Search: |
;160/7,8,9,291,296,300 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Caun; Peter M.
Attorney, Agent or Firm: Lerner; Herbert L.
Parent Case Text
This is a division of application Ser. No. 692,274, filed June 3,
1976, now abandoned.
Claims
We claim:
1. In a roller blind with a horizontally oriented winding shaft, a
safety device for arresting unrolling of the blind in the event of
failure of support means for the blind, which comprises a shaft
butt coupled to one end of the winding shaft to prevent rotation of
the shaft butt relative to the winding shaft, at least one drive
disk disposed on said shaft butt which drive disk rotates with said
shaft butt, a bearing pin parallel to the axis of the shaft butt
extending from the peripheral region of said drive disk, a pawl
shaped inertial member pivotally mounted on said bearing pin which
is concentric to the center of gravity and perpendicular to the
lateral surfaces of said inertial member, and a housing having
internal teeth in which is disposed the shaft butt with the drive
disk and pivotally mounted inertial member whereby when said roller
blind is rolled down in normal operation said inertial member will
not change its position radially relative to said drive disk, but
with increased unrolling velocity said inertial member in the form
of a pawl will change its position radially relative to said drive
disk and engage the internal teeth of said housing to arrest
unrolling of the blind.
2. In a roller blind with a safety device according to claim 1,
wherein said inertial member is in normal operation held in its
rest position by a spring.
3. In a roller blind with a safety device according to claim 1,
wherein said inertial member is held in its arrested position by a
checking device.
4. In a roller blind with a safety device according to claim 1,
wherein said housing also serves as a pillow block for said winding
shaft.
5. In a roller blind with a safety device according to claim 1,
wherein said housing is symmetrical to permit insertion and
assembly on the left or the right side of the housing as desired of
the elements interacting with the housing including the shaft butt,
drive disk, bearing pin, and the inertial member.
Description
CROSS-REFERENCE TO RELATED APPLICATION
My cofiled U.S. application Ser. No. 692,275, now abandoned
entitled "Safety Device for Arresting Unrolling of Roller
Blinds".
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to roller blinds with a horizontally
oriented winding shaft and more particularly refers to a blind with
a safety device which blocks the winding shaft in the event of a
failure of the support or driving means and arrests unrolling.
2. Description of the Prior Art
Rolling gates and roller blinds with horizontal winding shafts,
hereinafter collectively referred to as roller blinds, are known in
the art. Unfortunately, failure of the driving mechanism or other
support controlling the unrolling of the blind would occur with the
result that the blind would make a rapid descent attaining
considerable gravitational momentum placing great stress on the
parts of the roller blind and often causing appreciable damage to
it.
The known safety devices to arrest the winding shaft of the roller
blindrely on the use of centrifugal force, which depends on the
speed of rotation of the shaft, and requires that it reach a
predetermined value which exceeds that of the normal unrolling
speed. A necessary condition for this safety device to respond is
therefore a sufficient height of fall of the roller blind, that is
a height required for the build-up of the necessary centrifugal
forces. However, this necessary falling distance which is
considerable may already lie in the danger range. In addition, the
safety device can be damaged or destroyed by the gravitational
momentum of the already unrolled portion of the roller blind.
SUMMARY OF THE INVENTION
An object of the invention is to provide a roller blind having a
horizontal winding shaft with a safety device which responds to the
angular velocity of the winding shaft, independently of the
centrifugal force.
With the foregoing and other objects in view, there is provided in
accordance with the invention, a roller blind with a horizontally
oriented winding shaft, a safety device for arresting unrolling of
the blind in the event of failure of support means for the blind,
which includes a shaft butt coupled to one end of the winding shaft
to prevent rotation of the shaft butt relative to the winding
shaft, at least one drive disk disposed on the shaft butt which
drive disk rotates with the shaft butt, a bearing pin parallel to
the axis of the shaft butt extending from the peripheral region of
the drive disk, a pawl shaped inertial member pivotally mounted on
the bearing pin which is concentric to the center of gravity and
perpendicular to the lateral surfaces of the inertial member and a
housing having internal teeth in which is disposed the shaft butt
with the drive disk and pivotally mounted inertial member whereby
when the roller blind is rolled down in normal operation the
inertial member will not change its position relative to the drive
disk, but with increased unrolling velocity the inertial member in
the form of a pawl will change its position relative to the drive
disk and engage the internal teeth of the housing to arrest
unrolling of the blind.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features which are considered as characteristic for the
invention are set forth in the appended claims.
Although the invention is illustrated and described herein as
embodied in safety device protecting roller blinds against
unrolling, it is nevertheless not intended to be limited to the
details shown, since various modifications and structural changes
may be made therein without departing from the spirit of the
invention and within the scope and range of equivalents of the
claims.
The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be
best understood from the following description when read in
connection with the accompanying drawings, in which:
FIG. 1 shows an exploded view of the safety device of the roller
blind;
FIG. 2 is a longitudinal cross-sectional view of the safety device
of the roller blind; and
FIG. 3 is a cross-sectional view along line II--II of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the invention, a stationary housing which has
internal teeth has disposed therein and supports a shaft butt
coupled to the winding shaft and secured thereto to prevent
rotation relative to it. At least one drive disk is placed on the
shaft butt and the drive disk carries, pivoted in the peripheral
region on a bearing pin oriented parallel to the shaft, an inertial
member which is designed as a locking pawl, which interacts with
the internal teeth of the housing. The pivot bearing is disposed
perpendicularly to the lateral surfaces of the internal member and
concentrically to its center of gravity.
With the arrangement according to the invention, a safety device
against unrolling is obtained, which does not interfere with
rolling-down of roller blinds in normal operation and which
responds without material delay if the support or drive means
acting on the winding shaft fails.
Tests have shown that a safety device designed in accordance with
the invention responds to an angle of rotation which corresponds to
one tooth pitch of the internal teeth upon an increase of the
angular velocity, i.e. that in the case of danger, less than
one-quarter of a revolution of the winding shaft, depending on the
tooth pitch, is sufficient to ensure that the winding shaft is
safely arrested. In this range, however, the gravitational momentum
of the unrolled portion of the roller blind is quite small so that
the forces to be taken up by the safety device are likewise very
small and therefore, the mechanical stress on the parts of the
safety device remains small.
According to one preferred embodiment of the invention, the
inertial member is held, in normal operation, in its rest position
by the force of a spring, which spring force, however, is made so
small that, in the case of danger, the inertial effect
predominates. Unintentional release of the safety device against
unrolling can be prevented by a checking device such as a detent or
a pawl, which holds the inertial member in the locking position
after the safety device has responded.
Advantageously, the housing which has the internal teeth is
designed so that it is usable as a bearing stand or pillow block
for the winding shaft. Further, the housing is preferably of
symetrical configuration with openings on both sides to permit the
elements of the safety device to be inserted from the one or the
other side as desired.
In the case of extremely heavy roller blinds, it may be
advantageous to provide an energy converter, e.g., a friction
clutch, between the safety device and the winding shaft.
Referring now to the drawings, the safety device against unrolling
shown in the embodiment example is composed of a stationary housing
1 designed as a pillow block, which has internal teeth 2 and which
can be closed off laterally by covers 6, 7 containing bearings 4,
5. A shaft butt 8 is supported in the bearings 4, 5, which shaft
butt is connected so as to be secure against relative rotation, to
the winding shaft, not shown, of a roller blind. Two drive disks 9,
10 are mounted on shaft butt 8 and likewise secured against
relative rotation and placed within the housing. The drive disks 9,
10 are connected to each other by spacer posts 11, 12, 13, the
spacer post 11 serving as the pivot bearing for an inertial member
14 with a locking pawl interacting with the internal teeth 2.
Inertial member 14 has a bearing hole 15 coaxial to its center of
gravity and perpendicular to its lateral surfaces.
A spring 16, which is attached at one end to a pin 17, holds the
inertial member 14 in the rest position, shown in solid lines in
FIG. 2. The inertial member 14 in the arresting or locking position
is shown in dotted lines in FIG. 2. In rolling down a rolling gate
or a roller blind in normal operation, the inertial member 14 will
not change its position relative to the drive disks 9, 10. However,
if an increased unrolling velocity occurs such as is the case, for
example, if the support or drive means fail, then the inertial
member 14 is forced by the force vector extending perpendicularly
to its line of gravity into the position shown by broken lines in
FIG. 2 and thereby, the winding shaft is blocked via the shaft butt
8 which is connected thereto.
* * * * *